Cormanthyr is one of many Tel'Quessir (elven and eladrin) empires that have graced Faerûn. For much of recent history it has been in ruin, though recently it has risen again under a new Coronal. Its capital, Cormanthor, was the first of any city to have a mythal created by wizardry, whereas previously, all mythals were created by elven High Magic. After the mythal was raised the capital was referred to as Myth Drannor.

The early millennia of Cormanthyr were relatively uneventful. The title of Coronal was passed on through five more elves by -223 DR, when Eltargrim Irithyl took the throne.[8][9][10][11] During this time, most of their conflicts came with the drow, who built the Twisted Tower and effected raids upon the elves and surrounding lands. Also during this time, the humans and dwarves began to settle on the fringes of Cormanthor, which made the elves nervous but led to Eltargrim's most renowned changes.

Following his interpretation of Coronal Oacenth's wishes, Eltargrim decided to embrace the approach of other races rather than be in conflict with them. In 220 DR, he opened the forests to any non-elf wizards and druids as well as non-human settlers.[9][12][13][14][15] By 261 DR, he extended the Opening to the city of Myth Drannor despite rebellion and attacks on his life, and the city flourished for four hundred years.[9][14][16]

However, in 661 DR, four centuries after the Opening, Eltargrim died, leaving a lone heir, Aravae Irithyl, who was unready to take the throne.[17][18] Three years later, she was murdered, and left no heir.[19][9][18] In 666 DR, the powerful wizard Srinshee enacted the Claiming Ceremony that was needed to identify a new ruler of Cormanthyr, by drawing the famed Rulers' Blade. Over many days, elves died in attempts to draw the sword to no avail, and in the end, the Srinshee herself was resigned to draw it. While successful, she did not take on the role of Coronal, and instead departed for Arvandor to leave the elves to mull over their sins.[19][20][21][18] For the next fifty years, Cormanthyr fell under the rule of the Council of Twelve, and experienced great decline.[22][20][23]

For centuries to follow, the elves tried to contain the fiendish evil in Myth Drannor, having moved their power base to Elven Court. The realm became scattered and divided[27], and ultimately in 1344 DR the elves began the Retreat, when more than 90% of their population abandoned Cormanthor's woods for other settlements in the west.[28] The dream that was Cormanthyr was over.

The woods of Cormanthor became infested with drow after the retreat, who moved into the abandoned habitats of their kin. These drow attempted to seize the mythals and use the power for their own purposes.[29] However, their plans never came to fruition as Myth Drannor was invaded by Sarya Dlardrageth and her Daemonfey, who attempted to take control of the region in 1374 DR. In a complicated conflict involving the Zhentarim, Sembia and Hillsfar, as well as an Elven Crusade from Evereska, the Cormanthor War was fought in the woods and surrounding Dales. Eventually, House Dlardrageth fell to the Crusade, which became the Army of Myth Drannor led by Ilsevele Miritar. The Army of Myth Drannor eventually defeated the Zhentarim and seized control of Cormanthyr for the first time in seven centuries. In 1377 DR, the Srinshee returned and granted the Rulers' Blade to Ilsevele, who drew it successfully and became the first Coronal of the Present Age.[30]

In 1487 DR, after years of war against Netheril, Thultanthar fell upon Myth Drannor, destroying both cities and thereby the second Cormanthyr. Ilsevele and her surviving subjects fled to Semberholme.[31]

Elven Court was once the place where elves would seek advice and justice from their gods, the Seldarine. It was the seat of power for its own realm until it joined Cormanthyr during its founding, but remained a place of council for the Elves. After the fall of Myth Drannor, it became the seat of power for the Elves again during the Interim Years.

The former capital Myth Drannor, was once considered to be the most beautiful and largest of any of the cities in Faerûn. Unfortunately, the city was reduced to ruins for many centuries following the Weeping War and its subsequent infestation by fiends and later the Daemonfey. The city was once protected by a magical mythal which shielded Myth Drannor from harm, but it eventually fell into disrepair. The city was reclaimed in 1374 DR by the elves under Ilsevele Miritar, but destroyed in 1487 DR when Thultanthar fell upon it.[32]

Semberholme occupied the forests around Lake Sember atop a hilly region in southwestern Cormanthyr. During the height of Cormanthyr, it was known as a place of refuge for women, children, and the sick of the elven lands, as well as a safe haven with hidden limestone caverns where elves could hide in the event of war or disaster. It remained largely hidden and secret throughout most of its history.

Tangled Trees was a hidden realm in Cormanthyr where the worship of Rillifane Rallathil was dominant. The place was largely xenophobic, and many non-elves have been attacked or killed in efforts to enter the place.